I'm don't think you can AF with A mount lenses via a E to A mount adapter but you should be able to access AE and Aperture controls. Manual focus would be a better option underwater anyway so no great loss there.

The real issue with the VG cameras is that the control buttons are located underneath the flip out lcd screen, so a big mechanical housing with the lcd flipped out would be required. They are fun cameras though, I had a VG10.

AF and Iris is supported with the adapters, and the SLT LA-EA2 would probably be a pretty fun combo:

Hi , I'v just tested VG20 with Tokina 11-16 over LA-EA2 , works ok here is the result , but real issue is adapter works with iris minimum 3.5 , you must switch off AF ant the open iris if you want to , another issue is control of this camera , lanc works but only limited features ( very limited indeed ) strat stop function is enough for very limited period Equinox box hm ... I do not want it .. alternative russian made in st Petersbug , looks good , but with very limited controls and expencive arround 3k eu ....